Stabilized, laterovertically-expanding fusion cage systems

ABSTRACT

An intervertebral scaffolding system is provided having a laterovertically-expanding frame operable for a reversible collapse from an expanded state into a collapsed state, the laterovertically-expanding frame having a stabilizer that slidably engages with the distal region of the laterovertically-expanding frame and is configured for retaining the laterovertically-expanding frame from a lateral movement that exceeds the expanded state. The expanded state, for example, can be configured to have an open graft distribution window that at least substantially closes upon the reversible collapse.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/600,617, filed Jan. 20, 2015, which is hereby incorporated herein byreference in its entirety.

BACKGROUND

1. Field of the Invention

The teachings herein are directed to intervertebral scaffolding systemshaving a stabilizer for stabilizing and/or retaining support beams uponexpansion of the scaffolding in an intervertebral disc space.

2. Description of the Related Art

Bone grafts are used in spinal fusion, for example, which is a techniqueused to stabilize the spinal bones, or vertebrae, and a goal is tocreate a solid bridge of bone between two or more vertebrae. The fusionprocess includes “arthrodesis”, which can be thought of as the mendingor welding together of two bones in a spinal joint space, much like abroken arm or leg healing in a cast. Spinal fusion may be recommendedfor a variety of conditions that might include, for example, aspondylolisthesis, a degenerative disc disease, a recurrent discherniation, or perhaps to correct a prior surgery.

Bone graft material is introduced for fusion and a fusion cage can beinserted to help support the disc space during the fusion process. Infact, fusion cages are frequently used in such procedures to support andstabilize the disc space until bone graft unites the bone of theopposing vertebral endplates in the disc space. A transforaminal lumbarinterbody fusion (TLIF), for example, involves placement of posteriorinstrumentation (screws and rods) into the spine, and the fusion cageloaded with bone graft can be inserted into the disc space. Bone graftmaterial can be pre-packed in the disc space or packed after the cage isinserted. TLIF can be used to facilitate stability in the front and backparts of the lumbar spine promoting interbody fusion in the anteriorportion of the spine. Fusion in this region can be beneficial, becausethe anterior interbody space includes an increased area for bone toheal, as well as to handle increased forces that are distributed throughthis area.

Unfortunately, therein lies a problem solved by the teachings providedherein. Currently available systems can be problematic in that themethods of introducing the fusion cage and bone graft material leavespockets in regions of the intervertebral space that are not filled withbone graft material, regions in which fusion is desired for structuralsupport. These pockets can create a premature failure of the fusedintervertebral space due to forces that are distributed through theregions containing the pockets, for example, when the patient stands andwalks.

Traditional fusion cages, such as the Medtronic CAPSTONE cage, aredesigned to be oversized relative to the disc space to distract the discspace as the entire cage is inserted. However, this makes it difficultto insert and position properly. In response to the problem, the art hasdeveloped a number of new fusion cages, such as the Globus CALIBER cagewhich can be inserted at a low height and expanded vertically todistract the disc space. Unfortunately, these types of devices have thetypical graft distribution problem discussed above, in that they do notprovide a path for bone graft to be inserted and fill in the spacesurrounding the cage or within the cage. They have other problems aswell, including that the annulotomy must be large to accommodate a largeenough cage for stability, and this large opening necessitates moretrauma to the patient. Moreover, they can also create the additionalproblem of “backout”, in that they cannot expand laterally beyond theannulotomy to increase the lateral footprint of the cage relative tolateral dimension of the annulotomy. Since it takes several months forthe fusion to occur to completion in a patient, the devices have plentyof time to work their way out of the space through the large annulotomy.

Scaffolding systems may also suffer a lack of stability and/and or alack of a retention of structural components in a desired expansionconfiguration in the intervertebral space. As such, a multi-componentscaffolding system, for example, can benefit from an improved designthat adds stability through, for example, (i) enhancing the amount ofcontact between the scaffolding components upon expansion; and/or (ii)limiting the amount of expansion, or relative movement, that can occurbetween components upon expansion, or after expansion, in theintervertebral space. Such design considerations can, for example,address the problems of overexpansion of one component relative toanother due to, for example, variable stresses that might occur in theintervertebral space upon expansion or after expansion, stresses whichcan result in at least partial failure of the scaffolding system in theintervertebral space.

Accordingly, and for at least the above reasons, those of skill in theart will appreciate bone graft distribution systems that facilitate animproved distribution of graft material throughout the intervertebralspace. Such systems are provided herein, the systems configured to (i)effectively distribute bone graft material both from the system, andaround the system, to improve the strength and integrity of a fusion;(ii) reduce or eliminate the problem of failures resulting from a poorbone graft distribution; (iii) have a small maximum dimension in acollapsed state for a low-profile insertion into the annulus in aminimally-invasive manner, whether using only a unilateral approach or abilateral approach; (iv) laterally expand within the intervertebralspace to avoid backout of the system through the annulotomy; (v)vertically expand for distraction of the intervertebral space; (vi)provide an expansion in the intervertebral space without contracting thesystem in length to maintain a large footprint and an anterior positionadjacent to the inner, anterior annulus wall, distributing load over alarger area, anteriorly, against the endplates; (vii) and, incorporate astabilizer for stabilizing and/or retaining support beams upon expansionof the scaffolding in an intervertebral disc space.

SUMMARY

The teachings herein are directed to intervertebral scaffolding systemshaving a stabilizer for stabilizing and/or retaining support beams uponexpansion of the scaffolding in an intervertebral disc space. As such,the teachings herein are generally directed to an intervertebralscaffolding system.

The systems provided herein can comprise, for example, a central beamhaving a central beam axis; a proximal portion and a distal portion; atop surface with a first top-lateral surface and a second top-lateralsurface; a bottom surface with a first bottom-lateral surface and asecond bottom-lateral surface; a first side surface with a firsttop-side surface and a first bottom-side surface; and, a second sidesurface with a second top-side surface and a second bottom-side surface.The systems can also comprise a laterovertically-expanding frameconfigured for operably contacting the central beam to create anintervertebral scaffolding system in vivo. The frame can have acollapsed state and an expanded state, the expanded state operablycontacting with the central beam in the intervertebral space; a proximalportion having an end, a distal portion having an end, and a centralframe axis of the expanded state.

In some embodiments, the frame can be constructed to have a first topbeam including a proximal portion having an end and a distal portionhaving an end, the first top beam configured for contacting the firsttop-lateral surface of the central beam and the first top-side surfaceof the central beam in the expanded state, a central axis of the firsttop beam at least substantially on (i) a top plane containing thecentral axis of the first top beam and a central axis of a second topbeam and (ii) a first side plane containing the central axis of thefirst top beam and a central axis of a first bottom beam; the second topbeam including a proximal portion having an end and a distal portionhaving an end, the second top beam configured for contacting the secondtop-lateral surface of the central beam and the second top-side surfaceof the central beam in the expanded state, the central axis of thesecond top beam at least substantially on (i) the top plane and (ii) asecond side plane containing the central axis of the second top beam anda central axis of a second bottom beam; the first bottom beam includinga proximal portion having an end and a distal portion having an end, thefirst bottom beam configured for contacting the first bottom-lateralsurface of the central beam and the first bottom-side surface of thecentral beam in the expanded state, the central axis of the first bottombeam at least substantially on (i) a bottom plane containing the centralaxis of the first bottom beam and the central axis of the second topbeam and (ii) the first side plane; the second bottom beam including aproximal portion having an end and a distal region having an end, thesecond bottom beam configured for contacting the second bottom-lateralsurface of the central beam and the second bottom-side surface of thecentral beam in the expanded state, the central axis of the secondbottom beam being at least substantially on (i) the bottom plane and(ii) a second side plane containing the central axis of the secondbottom beam and the central axis of the second top beam.

The frame can also be constructed, for example, to have a plurality oftop connector elements configured to expandably connect the first topbeam to the second top beam, the expanding consisting of a flexing atleast substantially on the top plane; a plurality of bottom connectorelements configured to expandably connect the first bottom beam to thesecond bottom beam, the expanding consisting of a flexing at leastsubstantially on the bottom plane; a plurality of first side connectorelements configured to expandably connect the first top beam to thefirst bottom beam, the expanding consisting of a flexing at leastsubstantially on the first side plane; and, a plurality of second sideconnector elements configured to expandably connect the second top beamto the second bottom beam, the expanding consisting of a flexing atleast substantially on the second side plane

In some embodiments, the systems include a stabilizer that slidablyengages with the distal region of the first top beam, the first bottombeam, the second top beam, the second bottom beam, or a combinationthereof. The stabilizer can be configured for retaining the first topbeam, the first bottom beam, the second top beam, the second bottombeam, or the combination thereof, from a lateral movement that exceedsthe expanded state.

And, in some embodiments, the framing can be configured for engagingwith the central beam in vivo to support the framing in the expandedstate. Moreover, the connector elements can be struts configured to havea cross-sectional aspect ratio of longitudinal thickness to transversethickness ranging from 1:2 to 1:8, adapted to maintain structuralstiffness in the laterovertically expanding frame in a directionperpendicular to the central frame axis of the expanded state of theframe.

The stabilizer can be in an X-configuration. In some embodiments, theX-configuration can have a first top leg for slidably-engaging with thefirst top beam at an angle θ_(1T) with the lateral movement of the firsttop beam, first bottom leg for slidably engaging with the first bottombeam at an angle θ_(1B) with the lateral movement of the first bottombeam, a second top leg for slidably engaging with the second top beam atan angle θ_(2T) with the lateral movement of the second top beam, and asecond bottom leg for slidably engaging with the second bottom beam atan angle θ_(2B) with the lateral movement of the second bottom beam. Insome embodiments, each of the angles θ_(1T), θ_(1B), θ_(2T), θ_(2B),respectively, provide a tensile force for resisting the first top beam,the first bottom beam, the second top beam, and the second bottom beamfrom the lateral movement that exceeds the expanded state. In someembodiments, the stabilizer further comprises a point of attachment forreleasably attaching a guidewire for guiding the central beam into thelaterovertically expanding frame. And, in some embodiments, the firsttop leg, the first bottom leg, the second top leg, and the second bottomleg converge to form a hub having a point of attachment for releasablyattaching a guidewire for guiding the central beam into thelaterovertically expanding frame.

The stabilizer can be in an H-configuration. The H-configuration canhave a first vertical leg, a second vertical leg, and a cross-memberthat connects the first vertical leg at least substantially parallel tothe second vertical leg, the first vertical leg including a retainingsurface for engaging with the first top beam and the first bottom beam,the second vertical leg including a retaining surface for engaging withthe second top beam and the second bottom beam, and the cross memberproviding a tensile force for resisting the first top beam, the firstbottom beam, the second top beam, and the second bottom beam from thelateral movement that exceeds the expanded state. In some embodiments,the central beam has a horizontal groove configured complementary to thecross-member of the stabilizer, and the horizontal groove of the centralbeam slidably connects with the cross-member in the expanded state. Insome embodiments, the cross-member further comprises a vertical supportmember and the central beam has a vertical groove configuredcomplementary to the vertical support member of the stabilizer, and thevertical groove of the central beam slidably connects with the verticalsupport member in the expanded state. In some embodiments, thestabilizer further comprises a point of attachment for releasablyattaching a guidewire adapted for guiding the central beam into thelaterovertically expanding frame. And, in some embodiments, cross-memberincludes a first pillar and a second pillar that operably connect at ahub that has a point of attachment for releasably attaching a guidewirefor guiding the central beam into the laterovertically expanding frame.

In some embodiments, the systems are bone graft distribution systems. Inthese embodiments, the central beam can further comprise a graftingport. Likewise the expanding frame can open bone graft distributionwindows on the top, the bottom, the sides, or a combination thereof,upon expansion.

In some embodiments, the frame can be formed monolithically. In theseembodiments, each plurality connector elements can be struts; wherein,the top struts are configured monolithically integral to the first topbeam and the second top beam; and, the bottom struts are configuredmonolithically integral to the first bottom beam and the second bottombeam. The top struts and the bottom struts of thelaterovertically-expanding frame can each be configured to open a graftdistribution window upon expansion, expanding from the first top beam tothe second top beam, the first top beam to the first bottom beam, thesecond top beam to the second bottom beam, or the first bottom beam tothe second bottom beam. Likewise, in some embodiments, the top connectorstruts are configured monolithically integral to the first top beam andthe second top beam; and, the bottom struts are configuredmonolithically integral to the first bottom beam and the second bottombeam; the first side struts are configured monolithically integral tothe first top beam and the first bottom beam; and, the second sidestruts are configured monolithically integral to the second top beam andthe second bottom beam. It should be appreciated that, in suchembodiments, the top, bottom, first side, and second side of thelaterovertically-expanding frame cam form a monolithically integralframe.

The teachings are also directed to a method of fusing an intervertebralspace.

The methods can use the scaffolding systems taught herein. For example,the methods can include creating a point of entry into an intervertebraldisc, the intervertebral disc having a nucleus pulposus surrounded by anannulus fibrosis; removing the nucleus pulposus from within theintervertebral disc through the point of entry, leaving theintervertebral space for expansion of the scaffolding system of claim 1within the annulus fibrosis, the intervertebral space having a topvertebral plate and a bottom vertebral plate; inserting thelaterovertically expanding frame in the collapsed state through thepoint of entry into the intervertebral space; inserting the central beaminto the frame to form the scaffolding system; and, adding a graftingmaterial to the intervertebral space.

The step of creating the point of entry can comprise creating a lateraldimension of the point of entry ranging from about 5 mm to about 15 mm,and the amount of lateral expansion can be selected to exceed thelateral dimension of the point of entry. The step of expanding caninclude expanding the laterovertically expanding frame laterally to awidth that exceeds the width of the point of entry; and, inserting thecentral beam to expand the laterovertically expanding frame verticallyto support the frame in the expanded state. The step of inserting thecentral beam into the laterovertically expanding frame includes engaginga means for preventing the central beam from backing out of thelaterovertically-expanding frame after the expanding.

The teachings are also directed to a kit comprising a scaffolding systemtaught herein. The systems can include a cannula for inserting thescaffolding system into the intervertebral space; and, a guidewireadapted for guiding the central beam into the laterovertically expandingframe.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1I illustrate components of the graft distribution system,according to some embodiments.

FIGS. 2A-2F illustrate a method of using a bidirectionally-expandablecage, according to some embodiments.

FIGS. 3A-3D illustrate a bidirectionally-expandable cage for fusing anintervertebral disc space, according to some embodiments.

FIGS. 4A and 4B illustrate collapsed and expanded views of abidirectionally-expandable cage having a bone graft window on each wallfor fusing an intervertebral disc space, according to some embodiments.

FIGS. 5A-5D illustrate system for fusing an intervertebral disc space,according to some embodiments.

FIG. 6 is a diagram of a method of using a bidirectionally-expandablecage, according to some embodiments.

FIGS. 7A-7F illustrate some additional features of graft distributionsystems, according to some embodiments.

FIGS. 8A-8D illustrate components of a graft distribution kit, accordingto some embodiments.

FIGS. 9A-9C illustrate the expansion of a laterovertically-expandableframe in an intervertebral space, according to some embodiments.

FIGS. 10A-10C illustrate profiles of an expanded graft distributionsystem to highlight the exit ports and bone graft windows, according tosome embodiments.

FIGS. 11A and 11B compare an illustration of the graft distribution inplace to a test placement in a cadaver to show relative size, accordingto some embodiments.

FIGS. 12A-12C show x-rays of a placement in a cadaver, according to someembodiments.

FIGS. 13A-13D show orientations of the first top beam relative to thesecond top beam, first bottom beam relative to the second bottom beam,first top beam relative to the first bottom beam, and the second topbeam relative to the second bottom beam, according to some embodiments.

FIGS. 14A-14D illustrate components of a system having a stabilizer,wherein the stabilizer is in an X-configuration, according to someembodiments.

FIGS. 15A-15D illustrate components of a system having a stabilizer,wherein the stabilizer is in an H-configuration, according to someembodiments.

DETAILED DESCRIPTION OF THE INVENTION

The teachings herein are directed to intervertebral scaffolding systemshaving a stabilizer for stabilizing and/or retaining support beams uponexpansion of the scaffolding in an intervertebral disc space. Thesystems can have, for example, a central beam having a proximal portionhaving an end, a grafting portion having a top and a bottom, a distalportion having a end, a central beam axis, a graft distribution channelhaving an entry port at the end of the proximal portion, a top exit portat the top of the grafting portion, and a bottom exit port at the bottomof the grafting portion. These systems can also include alaterovertically-expanding frame having a lumen, a first top beam, asecond top beam, a first bottom beam, and a second bottom beam, eachhaving a proximal portion and a distal portion, and each operablyconnected to each other at their respective proximal portions and distalportions with connector elements to form the laterovertically-expandingframe that is operable for a reversible collapse from an expanded stateinto a collapsed state. The expanded state, for example, can beconfigured to have an open graft distribution window that at leastsubstantially closes upon the reversible collapse. In these embodiments,the laterovertically-expanding frame is adapted for receiving aninsertion of the central beam to form the graft distribution system.

In some embodiments, the systems can also include alaterovertically-expanding frame having a first top beam, a second topbeam, a first bottom beam, and a second bottom beam; wherein, the beamsare in an at least substantially parallel arrangement with each other,each having a proximal portion, a grafting portion, and a distalportion, and each operably connected to each other at their respectiveproximal portions and distal portions to form thelaterovertically-expanding frame in a square, cylindrical shape that isoperable for a reversible collapse from an expanded state into acollapsed state. The expanded state, for example, can be configured tohave an open graft distribution window that at least substantiallycloses upon the reversible collapse. In these embodiments, thelaterovertically-expanding frame is adapted for receiving an insertionof the central beam to form the graft distribution system.

The term “subject” and “patient” can be used interchangeably in someembodiments and refer to an animal such as a mammal including, but notlimited to, non-primates such as, for example, a cow, pig, horse, cat,dog; and primates such as, for example, a monkey or a human. As such,the terms “subject” and “patient” can also be applied to non-humanbiologic applications including, but not limited to, veterinary,companion animals, commercial livestock, and the like. Moreover, termsof degree are used herein to provide relative relationships between theposition and/or movements of components of the systems taught herein.For example, the phrase “at least substantially parallel” is used torefer to a position of one component relative to another. An axis thatis at least substantially parallel to another axis refers to anorientation that is intended, for all practical purposes to be parallel,but it is understood that this is just a convenient reference and thatthere can be variations due to stresses internal to the system andimperfections in the devices and systems. Likewise, the phrase “at leastsubstantially on a . . . plane” refers to an orientation or movementthat is intended, for all practical purposes to be on or near the planeas a convenient measure of the orientation or movement, but it isunderstood that this is just a convenient reference and that there canbe variations due to stresses internal to the system and imperfectionsin the devices and systems. Likewise, the phrase “at least substantiallycoincident” refers to an orientation or movement that is intended, forall practical purposes to be on or near, for example, an axis or a planeas a convenient measure of the orientation or movement, but it isunderstood that this is just a convenient reference and that there canbe variations due to stresses internal to the system and imperfectionsin the devices and systems.

FIGS. 1A-1I illustrate components of the system, according to someembodiments. As shown in FIG. 1A, the graft distribution systems 100 canhave a central beam 101 with a central beam axis 105, a graftdistribution channel with an entry port 135 in fluid communication witha top exit port 140, and a bottom exit port 141. The central beam 101can also have a proximal portion 111 having and end with the entry port135, a grafting portion 112 having the top exit port 140 and the bottomexit port 141, and a distal portion (not shown). The central beam 101can also be sized to have a transverse cross-section 110 having amaximum dimension ranging from 5 mm to 15 mm for placing the centralbeam 101 into an intervertebral space through an annular opening havinga maximum lateral dimension ranging from 5 mm to 15 mm, theintervertebral space having a top vertebral plate and a bottom vertebralplate. The central beam 101 can also have a top surface 115 with a firsttop-lateral surface 117 and a second top-lateral surface 119, a bottomsurface 120 with a first bottom-lateral surface 122 and a secondbottom-lateral surface 124, a first side surface 125 with a firsttop-side surface 127 and a first bottom-side surface 129, and a secondside surface 130 with a second top-side surface 132 and a secondbottom-side surface 134.

In some embodiments, the central beam can have transversecross-sectional lateral dimension ranging from about 5 mm to about 15mm. In some embodiments, the vertical dimension of the central beam canrange from about 4 mm to about 12 mm, about 5 mm to about 11 mm, about 6mm to about 10 mm, and about 7 mm to about 9 mm, about 6 mm to about 8mm, about 6 mm, or any range or amount therein in increments of 1 mm. Insome embodiments, the lateral dimension of the central beam can rangefrom about 5 mm to about 15 mm, about 6 mm to about 14 mm, about 7 mm toabout 13 mm, about 8 mm to about 12 mm, about 10 mm, or any range oramount therein in increments of 1 mm. In some embodiments, transversecross-section of the central beam has an area with an effective diameterranging from about 2 mm to about 20 mm, from about 3 mm to about 18 mm,from about 4 mm to about 16 mm, from about 5 mm to about 14 mm, fromabout 6 mm to about 12 mm, from about 7 mm to about 10 mm, or any rangetherein. In some embodiments, the low profile has an area with adiameter of 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm,or any range therein, including any increment of 1 mm in any suchdiameter or range therein. In some embodiments, the width (mm)×height(mm) of the central beam can be 9.0×5.0, 9.0×6.0, 9.0×7.0, 9.0×8.0,9.0×9.0, and 9.0×10.0, or any deviation in dimension therein inincrements of +/−0.1 mm. And, in some embodiments, the central beam canhave a transverse cross-sectional lateral or vertical dimension thatranges from 6.5 mm to 14.0 mm.

As shown in FIGS. 1B and 10, the system 100 can also comprise alaterovertically-expanding frame 149 configured for operably contactingthe central beam 101 to create a graft distribution system 100 in vivo,the frame 149 having a collapsed state 149 c with a transverse crosssection 149 ct having a maximum dimension ranging from 5 mm to 15 mm forplacing the frame 149 in the intervertebral space through the annularopening for expansion. Likewise, the frame 149 can also have an expandedstate 149 e with a transverse cross section 149 et having a maximumdimension ranging from 6.5 mm to 18 mm for retaining the frame 149 inthe intervertebral space, the expanded state operably contacting withthe central beam 101 in the intervertebral space. The frame 149 can bedefined as including a proximal portion 111 having an end, a graftingportion 112, a distal portion (not shown) having an end, and a centralframe axis 113 of the expanded state 149 e.

In some embodiments, the frame can have transverse cross-sectionallateral dimension in the collapsed state ranging from about 5 mm toabout 15 mm. In some embodiments, the vertical dimension of the frame inthe collapsed state can range from about 4 mm to about 12 mm, about 5 mmto about 11 mm, about 6 mm to about 10 mm, and about 7 mm to about 9 mm,about 6 mm to about 8 mm, about 6 mm, or any range or amount therein inincrements of 1 mm. In some embodiments, the lateral dimension of theframe in the collapsed state can range from about 5 mm to about 15 mm,about 6 mm to about 14 mm, about 7 mm to about 13 mm, about 8 mm toabout 12 mm, about 10 mm, or any range or amount therein in incrementsof 1 mm. In some embodiments, transverse cross-section of the frame inthe collapsed state has an area with an effective diameter ranging fromabout 2 mm to about 20 mm, from about 3 mm to about 18 mm, from about 4mm to about 16 mm, from about 5 mm to about 14 mm, from about 6 mm toabout 12 mm, from about 7 mm to about 10 mm, or any range therein. Insome embodiments, the low profile has an area with a diameter of 2 mm, 4mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, or any range therein,including any increment of 1 mm in any such diameter or range therein.In some embodiments, the width (mm)×height (mm) of the frame in thecollapsed state can be 9.0×5.0, 9.0×6.0, 9.0×7.0, 9.0×8.0, 9.0×9.0, and9.0×10.0, or any deviation in dimension therein in increments of +/−0.1mm. In some embodiments, the frame can have a transverse cross-sectionaldimension, lateral or vertical in the expanded state ranging from 4.0 mmto 18 mm, from 5.0 mm to 19.0 mm, from 6.0 mm to 17.5 mm, from 7.0 mm to17.0 mm, from 8.0 mm to 16.5 mm, from 9.0 mm to 16.0 mm, from 9.0 mm to15.5 mm, from 6.5 mm to 15.5 mm, or any range or amount therein inincrements of +/−0.1 mm.

The term “collapsed state” can be used to refer to a configuration ofthe frame in which the transverse cross-sectional area, or profile, isat least substantially at it's minimum, and the term “expanded state”can be used to refer to a configuration of the frame that is expanded atleast substantially beyond the collapsed state. In this context, a frameis expanded at least “substantially” beyond the collapsed state when abone graft window of the frame has opened from the closed configurationby at least a 20% increase area of the bone graft window from thecollapsed state. In some embodiments, the frame is expanded at least“substantially” beyond the collapsed state when a bone graft window ofthe frame has opened by at least a 15%, 20%, 25%, 30%, 35%, 40%, 45%,50%, 60%, 70%, 80%, 90%, 100%, 150%, 200%, 250%, 300%, or more whencompared to the bone graft window from the collapsed state. In someembodiments, the frame is expanded at least “substantially” beyond thecollapsed state when a bone graft window of the frame has opened by atleast 2×, 3×, 5×, 10×, 15×, 20×, or more when compared to the bone graftwindow from the collapsed state.

In some embodiments, the laterovertically expandable frames are createdin an expanded state. And the expanded state can include a state that isat least 30%, at least 40%, at least 50%, at least 60%, at least 70%, atleast 80%, at least 90%, or at least 95% of the full expansion. The term“full expansion” can be used to refer to an extent of expansion uponwhich a connector element begins to fatigue, fail, or crack; or, in someembodiments, strain beyond 10%, 20%, or 30%.

The frame 149 can be configured to have a first top beam 150 including aproximal portion 111 having an end, a grafting portion 112, and a distalportion (not shown) having an end, the first top beam 150 configured forcontacting the first top-lateral surface 117 of the central beam and thefirst top-side surface 127 of the central beam 101 in the expanded state149 e, the central axis of the first top beam at least substantially on(i) a top plane containing the central axis of the first top beam andthe central axis of a second top beam and (ii) a first side planecontaining the central axis of the first top beam and the central axisof a first bottom beam. Likewise the frame 149 can be configured to havea second top beam 160 including a proximal portion 111 having an end, agrafting portion 112 having an end, and a distal portion (not shown)having an end, the second top beam 160 configured for contacting thesecond top-lateral surface 119 of the central beam 101 and the secondtop-side surface 132 of the central beam 101 in the expanded state 149e, the central axis of the second top beam at least substantially on (i)the top plane and (ii) a second side plane containing the central axisof the second top beam and the central axis of a second bottom beam.Likewise the frame 149 can be configured to have a first bottom beam 170including a proximal portion 111 having an end, a grafting portion 112,and a distal portion (not shown) having an end, the first bottom beam170 configured for contacting the first bottom-lateral surface 122 ofthe central beam 101 and the first bottom-side surface 129 of thecentral beam 101 in the expanded state 149 e, the central axis of thefirst bottom beam at least substantially on (i) a bottom planecontaining the central axis of the first bottom beam and the centralaxis of a second top beam and (ii) the first side plane. Likewise theframe 149 can be configured to have a second bottom beam 180 including aproximal portion 111 having an end, a grafting portion 112 having anend, and a distal region (not shown) having an end, the second bottombeam 160 configured for contacting the second bottom-lateral surface 124of the central beam 101 and the second bottom-side surface 134 of thecentral beam 101 in the expanded state 149 e, the central axis of thesecond bottom beam being at least substantially on (i) the bottom planeand (ii) a second side plane containing the central axis of the secondbottom beam and the second top beam.

In some embodiments, the central axis of the first top beam 150 can beat least substantially parallel to the central beam axis 105. Likewisethe frame 149 can be configured to have a second top beam 160 includinga proximal portion 111 having an end, a grafting portion 112 having anend, and a distal portion (not shown) having an end, the second top beam160 configured for contacting the second top-lateral surface 119 of thecentral beam 101 and the second top-side surface 132 of the central beam101 in the expanded state 149 e, the central axis of the second top beam160 being at least substantially parallel to the central beam axis 105.Likewise the frame 149 can be configured to have a first bottom beam 170including a proximal portion 111 having an end, a grafting portion 112,and a distal portion (not shown) having an end, the first bottom beam170 configured for contacting the first bottom-lateral surface 122 ofthe central beam 101 and the first bottom-side surface 129 of thecentral beam 101 in the expanded state 149 e, the central axis of thefirst bottom beam 170 being at least substantially parallel to thecentral beam axis 105. Likewise the frame 149 can be configured to havea second bottom beam 180 including a proximal portion 111 having an end,a grafting portion 112 having an end, and a distal region (not shown)having an end, the second bottom beam 160 configured for contacting thesecond bottom-lateral surface 124 of the central beam 101 and the secondbottom-side surface 134 of the central beam 101 in the expanded state149 e, the central axis of the second bottom beam 180 being at leastsubstantially parallel to the central beam axis 105.

As shown in FIG. 1D, the systems provided herein have the layered effectfrom the frame on the central beam that provides an additive dimension,both laterally and vertically. The added dimension allows for a lowprofile entry of the system into the intervertebral disc space, a widelateral profile after expansion in vivo to avoid backout, as well as asleeve for safe insertion of the central beam between the top endplateand bottom endplate in the intervertebral space. In some embodiments,the first top beam, second top beam, first bottom beam, and secondbottom beam can each have a transverse cross-sectional wall thicknessadding to the respective central beam dimension, the thickness rangingfrom about 0.5 mm to about 5.0 mm, from about 0.75 mm to about 4.75 mm,from about 1.0 mm to about 4.5 mm, from about 1.25 mm to about 4.25 mm,from about 1.5 mm to about 4.0 mm, from about 1.75 mm to about 3.75 mm,from about 2.0 mm to about 3.5 mm, from about 2.25 mm to about 3.25 mm,or any range therein in increments of 0.05 mm. In some embodiments, thefirst top beam, second top beam, first bottom beam, and second bottombeam can each have a transverse cross-sectional wall thickness adding tothe respective central beam dimension, the thickness ranging from about1.5 mm to about 2.5 mm, including 1.5, 1.75, 2.0, 2.25, 2.5, or anamount therein in increments of 0.05 mm.

The beams of the laterovertically-expanding frame 149 can be operablyconnected through connector elements. As such, the frame 149 can includea plurality of proximal top connector elements 191 configured toexpandably connect the proximal portion 111 of the first top beam 150 tothe proximal portion 111 of the second top beam 160, the expandingconsisting of a flexing at least substantially on a top plane containingthe central axis of the first top beam 150 and the central axis of thesecond top beam 160. Likewise the frame 149 can be configured to have aplurality of distal top connector elements (not shown) configured toexpandably connect the distal portion of the first top beam 150 to thedistal portion of the second top beam 160, the expanding consisting of aflexing at least substantially on the top plane.

Likewise the frame 149 can be configured to have a plurality of proximalbottom connector elements 193 configured to expandably connect theproximal portion 111 of the first bottom beam 170 to the proximalportion 111 of the second bottom beam 180, the expanding consisting of aflexing at least substantially on a bottom plane containing the centralaxis of the first bottom beam 170 and the central axis of the secondbottom beam 180. Likewise the frame 149 can be configured to have aplurality of distal bottom connector elements (not shown) configured toexpandably connect the distal portion of the first bottom beam 170 tothe distal portion of the second bottom beam 180, the expandingconsisting of a flexing at least substantially on the bottom plane.

Likewise the frame 149 can be configured to have a plurality of proximalfirst side connector elements 195 configured to expandably connect theproximal portion 111 of the first top beam 150 to the proximal portion111 of the first bottom beam 170, the expanding consisting of a flexingat least substantially on a first side plane containing the central axisof the first top beam 150 and the central axis of the first bottom beam170; a plurality of distal first side connector elements (not shown)configured to expandably connect the distal portion of the first topbeam 150 to the distal portion of the first bottom beam 170, theexpanding consisting of a flexing at least substantially on the firstside plane. Likewise the frame 149 can be configured to have a pluralityof proximal second side connector elements 197 configured to expandablyconnect the proximal portion 111 of the second top beam 160 to theproximal portion 111 of the second bottom beam 170, the expandingconsisting of a flexing at least substantially on a second side planecontaining the central axis of the second top beam 160 and the centralaxis of the second bottom beam 180; a plurality of distal second sideconnector elements (not shown) configured to expandably connect thedistal portion of the second top beam 160 to the distal portion of thesecond bottom beam 180, the expanding consisting of a flexing at leastsubstantially on the second side plane.

In some embodiments, each plurality of proximal connector elements canbe configured as proximal struts in an at least substantially parallelalignment in the expanded state and the collapsed state; and, eachplurality distal connector elements are distal struts can be configuredin an at least substantially parallel alignment in the expanded stateand the collapsed state. As such, the proximal top struts can beconfigured monolithically integral to the first top beam and the secondtop beam and adapted to flex toward the distal top struts duringcollapse; and, the distal top struts can be configured monolithicallyintegral to the first top beam and the second top beam and adapted toflex toward the proximal top struts during collapse. Likewise, theproximal bottom struts can be configured monolithically integral to thefirst bottom beam and the second bottom beam and adapted to flex towardthe distal bottom struts during collapse; and, the distal bottom strutscan be configured monolithically integral to the first bottom beam andthe second bottom beam and adapted to flex toward the proximal bottomstruts during collapse. Likewise, the proximal first side struts can beconfigured monolithically integral to the first top beam and the firstbottom beam and adapted to flex toward the distal first side strutsduring collapse; and, the distal first side struts can be configuredmonolithically integral to the first top beam and the first bottom beamand adapted to flex toward the proximal first side struts duringcollapse. Likewise, the proximal second side struts can be configuredmonolithically integral to the second top beam and the second bottombeam and adapted to flex toward the distal second side struts duringcollapse; and, the distal second side struts can be configuredmonolithically integral to the second top beam and the second bottombeam and adapted to flex toward the proximal second side struts duringcollapse.

As shown in FIG. 1D, the frame 149 can be configured for slidablyengaging with the central beam 101 in vivo following placement of thecentral beam 101 in the intervertebral space through the annularopening, the slidably engaging including translating the central beam101 into the frame 149 from the proximal end 11 of the frame 149 towardthe distal end of the frame 149 in vivo; the translating includingkeeping the central beam axis 105 at least substantially coincident withthe central frame axis 113 during the translating to create the graftdistribution system 100 in vivo through the annular opening. The system100 can also be configured to form a top graft-slab depth 199 t betweenthe top surface 115 of the central beam 101 and the top vertebralendplate; and, a bottom graft-slab depth 199 b (not shown) between thebottom surface 120 of the central beam 101 and the bottom vertebralendplate in vivo. And, in some embodiments, the transverse cross-section110 of the system 100 in vivo is greater than the maximum lateraldimension of the annular opening to avoid backout.

One of skill will appreciate that the central beam can have anyconfiguration that would be operable with the teachings provided herein.In some embodiments, criteria for a suitable central beam may include acombination of a material and configuration that provides a suitablestiffness. In some embodiments, the central beam can comprise an I-beam.An example of an I-beam configuration and a complementarylaterovertically expandable cage are shown in FIGS. 1E and 1F.

One of skill will further appreciate that the central beam can have anyone or any combination of graft port configurations that would beoperable with the teachings provided herein. In some embodiments,criteria for a suitable graft port configuration may include acombination of port size, number of ports, and placement of ports. Insome embodiments, the central beam can comprise a side graft port.

One of skill will further appreciate that the connector elements canvary in design but should meet the constraints as taught herein. In someembodiments, for example each of the connector elements 191,193,195,197can have a cross-sectional aspect ratio of longitudinal thickness totransverse thickness ranging from 1:2 to 1:8. A section of a connectorelement is shown in FIG. 1G.

As such, the systems can also include an improved, low-profile,intervertebral disc cage that expands bidirectionally. Consistent withthe teachings herein, the cages offer several improvements to the artthat include, for example, preventing the cage from backing out of theannulus fibrosis after expansion in an intervertebral disc space. Assuch, the terms “cage,” “scaffold” and “scaffolding”, for example, canbe used interchangeably with “laterovertically expandable frame”,“expandable frame”, or “frame”, in some embodiments. The cages have theability to at least (i) laterally expand within the intervertebral spaceto avoid backout of the device through the annulotomy, (ii) verticallyexpand for distraction of the intervertebral space, (iii) provideadditional space within the device in the annulus for the introductionof graft materials; (iv) maintain a large, footprint to distribute loadover a larger area against the endplate, for example, by not contractingin length to expand in height and/or width; and, (v) insert into theannulus in a minimally-invasive manner using only a unilateral approach.

FIGS. 2A-2F illustrate a method of using a bidirectionally-expandablecage, according to some embodiments. As shown in FIGS. 2A-2B, an annulus205 is prepared with an annulotomy serving as a single point of entry210 and an intervertebral space 215 for insertion of a bidirectionallyexpandable cage system 250. As shown in FIGS. 2C-2F, the system 250 hasa cage 255 having a proximal end 256, a distal end 257, and a lumen 258that communicates with the intervertebral space 215 through anexpandable/collapsible bone graft window 259; a shim core 260 having atapered nose 262 at the distal end of the shim core 260; a releasablyattachable rail beam 265; a pusher 270 that slidably translates over theshim core 260 and the rail beam 265; a trial shim 275 having a shoulder277 and slidably translating over the rail beam 265 and shim core 260into the lumen 258 of the cage 255, and a permanent shim 280 having ashoulder 282 and slidably translating over the rail beam 265 and shimcore 260 into the lumen 258 of the cage 255.

The procedure for implanting the cage 255 begins in FIG. 2A, includinginserting a cannula (not shown) with a bullet-nosed obturator throughthe single point of entry 210 and inside the intervertebral disc space215 until contacting the opposing wall of the annulus 205. The cannula(not shown) depth is used to select the desired length of the cage 255.The shim core 260 is loaded with bone graft material and the rail beam265 is releasably attached to the shim core 260. The cage 255 is loadedonto the rail beam 265 and pushed onto the shim core 260 and into thecannula (not shown) using the pusher 270 until the distal end 257 of thecage 255 contacts the back of the tapered nose 262 of the shim core 260as shown in FIG. 2A. The assembly of the shim core 260 and the cage 255are inserted into the intervertebral space 215, and the cannula (notshown) is removed as shown in FIG. 2B. The lumen 258 of the cage 255 isloaded with bone graft material, and the trial shim 275 is slidablytranslated over the rail beam 265 and the shim core 260 into the lumen258 of the cage 255 as shown in FIG. 2C. A variety of sizes of the trialshim 275 can be tested until the largest trial shim 275 that will fit isfound, or until the trial shim having the desired vertical and lateraldimensions for expansion is used, in order to laterovertically expandthe cage 255 as desired. The trial shim 275 is then removed, and thelumen 258 of the cage 255 is again filled with bone graft material withthe shim core 260 remaining in place as shown in FIG. 2D. The permanentshim 280 is then slidably translated along the rail beam 265 and theshim core 260 into the intervertebral space 215 using the pusher 270until the distal end 257 of the cage 255 contacts the back of thetapered nose 262 of the shim core 260 to maintain the desiredlaterovertical expansion of the cage 255 as shown in FIG. 2E. The railbeam 265 is then disconnected from the shim core 260 as shown in FIG.2F.

It should be appreciated that the annulotomy can have nearly anydimension considered desirable to one of skill in the art. Theannulotomy can have a vertical dimension, for example, that is thedistance between a top vertebral plate and a bottom vertebral plate, thetop vertebral plate and the bottom vertebral plate defining the upperand lower borders of the intervertebral disc space. In some embodiments,the vertical dimension can range from about 4 mm to about 12 mm, about 5mm to about 11 mm, about 6 mm to about 10 mm, and about 7 mm to about 9mm, about 6 mm to about 8 mm, about 6 mm, or any range or amount thereinin increments of 1 mm. In some embodiments, the lateral dimension of thesingle point of entry can range from about 5 mm to about 15 mm, about 6mm to about 14 mm, about 7 mm to about 13 mm, about 8 mm to about 12 mm,about 10 mm, or any range or amount therein in increments of 1 mm. Insome embodiments, the single point of entry has an area with a diameterranging from about 2 mm to about 20 mm, from about 3 mm to about 18 mm,from about 4 mm to about 16 mm, from about 5 mm to about 14 mm, fromabout 6 mm to about 12 mm, from about 7 mm to about 10 mm, or any rangetherein. In some embodiments, the low profile has an area with adiameter of 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm,or any range therein, including any increment of 1 mm in any suchdiameter or range therein. The low profile dimensions of the cagestaught herein are designed to fit within these dimensions.

One of skill will also appreciate that there are several methods anddevices that could be used to expand the cage. In some embodiments, theexpanding includes using a means for (i) laterovertically expanding thecage and (ii) creating a convex surface that at least substantiallycomplements the concavity of a surface of a vertebral endplate thatcontacts the pair of top beams or the pair of bottom beams.

One of skill will also appreciate a method that distracts theintervertebral space and laterally expands the cage to avoid back-out.As such, in some embodiments, the expanding includes introducing alaterovertical expansion member into the intervertebral space throughthe single point of entry and into the cage, the lateroverticalexpansion member configured to provide a vertical force through the cageand into the top vertical endplate and bottom vertical endplate todistract the intervertebral space; and, a lateral force on the firstside wall and the second side wall to expand the cage to a width that isgreater than the lateral dimension of the single point of entry toprevent the bidirectionally-expandable cage from backing out of theannulus fibrosis after the expanding.

One of skill will also appreciate having a method for passing bonegrafting material into the intervertebral space. As such, thelaterovertical expansion member can include a port for introducing thegrafting material into the intervertebral space. The methods and systemsprovided herein include the use of bone graft materials known to one ofskill. Materials which may be placed or injected into the intervertebralspace include solid or semi-solid grafting materials, bone from removedfrom patient's facet, an iliac crest harvest from the patient, and bonegraft extenders such as hydroxyapatite, demineralized bone matrix, andbone morphogenic protein. Examples of solid or semi-solid graftingmaterial components include solid fibrous collagen or other suitablehard hydrophilic biocompatible material. Some materials may also includeswelling for further vertical expansion of the intervertebral discspace.

One of skill will also appreciate having a method for retaining thelaterovertical expansion member in the cage. As such, the introducingcan include engaging a ratchet mechanism comprising a protuberance onthe laterovertical expansion member that engages with a strut of thecage to prevent the cage from backing out of the annulus fibrosis afterthe expanding. The ratchet mechanism can be, for example, similar to azip-tie ratchet mechanism having a gear component and a pawl component.In some embodiments, the cage has the gear component, for example,including the struts; and, the laterovertical expansion member is a shimdevice having the pawl component, for example, a projection that canangle toward the proximal end of the expansion member or away from thedirection of insertion of the shim device. In some embodiments, the cagehas the pawl component, for example, including the struts; and, thelaterovertical expansion member is a shim device having the gearcomponent, for example, a series of projections. In some embodiments, aprojection can angle from about 5° to about 75° toward the proximal endof the expansion member or away from the direction of insertion of theshim device.

One of skill will also appreciate having a method of designing the shapeof the cage upon expansion. As such, in some embodiments, the expandingincludes selecting a shim configured to create a convex surface on thetop surface of the top wall to at least substantially complement theconcavity of the respective top vertebral plate, and/or the bottomsurface of the bottom wall to at least substantially complement theconcavity of the respective bottom vertebral plate. In some embodiments,the expanding includes selecting a shim configured to vertically expandthe distal end of the cage more than the proximal end of the cage. And,in some embodiments, the expanding includes selecting a shim configuredto laterally expand the distal end of the cage more than the proximalend of the cage.

FIGS. 3A-3D illustrate collapsed and expanded views of abidirectionally-expandable cage for fusing an intervertebral disc space,according to some embodiments. FIGS. 3A and 3C show an expandedconfiguration, and FIGS. 3B and 3D show a collapsed configuration. Thecage 300 can comprise at least 4 walls 302,304,306,308 that form acylinder having a long axis 309, the at least 4 walls 302,304,306,308including a top wall 302 forming a top plane and having a top surfacewith protuberances (not shown) adapted to contact the top vertebralplate (not shown); a bottom wall 304 forming a bottom plane and having abottom surface with protuberances (not shown) adapted to contact thebottom vertebral plate (not shown); a first side wall 306 forming afirst side wall plane; and, a second side wall 308 forming a second sidewall plane. In these embodiments, each of the walls 302,304,306,308 canhave at least 2 longitudinal beams, such that a rectangular cylinder canhave a total of 4 longitudinal beams 312,314,316,318; and, a pluralityof struts 333 that (i) stack in the collapsed state of the cage 300, asshown in FIGS. 3B and 3D, to minimize void space in their respectivewall for a low profile entry of the cage 300 both vertically andlaterally into a single point of entry (not shown) into anintervertebral disc space (not shown) and (ii) deflect upon expansion toseparate the at least 2 longitudinal beams of the total of 4longitudinal beams 312,314,316,318 in the rectangular cylinder in theirrespective wall 302,304,306,308. In addition, the cage 300 can beconfigured to expand laterally in the intervertebral space (not shown)to a size greater than a lateral dimension of the single point of entry(not shown to prevent the bidirectionally-expandable cage 300 frombacking out of the annulus fibrosis (not shown) after the expandingshown in FIGS. 3A and 3C.

It should be appreciated that the collapsed configuration includes thedesign of a low profile entry through the annulus fibrosis to allow fora minimally-invasive procedure. In order to facilitate the use of aminimally-invasive procedure, the low profile entry of the collapsedconfiguration should be a substantially small area of entry having adiameter ranging, for example, from about 5 mm to about 12 mm for thesingle point of entry through the annulus fibrosis. In some embodiments,the low profile has an area with a diameter ranging from about 2 mm toabout 20 mm, from about 3 mm to about 18 mm, from about 4 mm to about 16mm, from about 5 mm to about 14 mm, from about 6 mm to about 12 mm, fromabout 7 mm to about 10 mm, or any range therein. In some embodiments,the low profile has an area with a diameter of 2 mm, 4 mm, 6 mm, 8 mm,10 mm, 12 mm, 14 mm, 16 mm, 18 mm, or any range therein, including anyincrement of 1 mm in any such diameter or range therein.

One of skill will appreciate that a variety of strut configurations maybe contemplated to minimize void space for the low profile entry of thecage into the intervertebral space. In some embodiments, each wall ofthe cage has a series of v-shaped struts 333 that (i) stack in aclosed-complementary configuration 344 in the collapsed state tominimize void space in their respective wall for the low profile entryof the cage both vertically and laterally into the intervertebral space,and (ii) deflect upon expansion in a plane that is at leastsubstantially parallel to the plane of their respective wall to anopen-complementary configuration 355 to separate the at least 2longitudinal beams of the total of 4 longitudinal beams 312,314,316,318in the rectangular cylinder in their respective wall and open a bonegraft window 366 to pass a bone graft material into the intervertebralspace in the expanded configuration. In some embodiments, the cage 300is configured to accommodate the lateral dimension of the single pointof entry ranging from about 5 mm to about 15 mm.

The v-shaped struts can be “V” shaped slots projected through each ofthe cage walls starting at a distance of 2 mm (0.5-4) from each cornerof the cage to effectively render the “V” shaped struts in the midregion of the wall faces, in which the struts can be fabricated ascontinuous with L shaped beams on the corners. The slots can be cut suchthat they are projected perpendicular to the faces or angled distallyfrom the outside of the cage to the inside of the cage. The distallyangled projection can facilitate insertion of the shims taught herein.And, the proximal faces of the corners of the beams can also haveinward, distally angled chamfers to facilitate insertion of the shimstaught herein. The struts can be uniform in thickness in theproximal-distal direction. In some embodiments, the struts range fromabout 0.2 mm to about 1.0 mm, from about 0.3 mm to about 0.9 mm, fromabout 0.4 mm to about 0.8 mm, from about 0.5 mm to about 0.7 mm inthickness, or any range therein in increments of about 0.1 mm. Thevertex of the “V” strut can trace along the center axis of the each ofthe side faces and can be radiused to dimension of 0.031″(0.005-0.062″), in some embodiments, to prevent stress cracking.Moreover, the shape of the strut or the slot projections can also be C,U, or W, in some embodiments. The struts can be 4 times thicker in thedirection perpendicular to the long axis of the cage than in thedirection of the long axis of the cage. In some embodiments, thisthickness ratio can range from about 2× to about 8×, from about 3× toabout 7×, from about 4× to about 6×, about 5×, or any range therein inincrements of 1×. This thickness can help maintain a high structuralstiffness and strength in the direction perpendicular to theproximal-distal axis so that the transverse cross section (perpendicularto the proximal-distal axis) shape is maintained during and afterinsertion of the cage into the intervertebral disc space.

In some embodiments, the angle of each strut can range from about140°-170° as measured at the vertex in the non-stressed state. In theseembodiments, the angle facilitates flexion of the legs of each struttowards each other upon moderate inward pressure to collapse the cagefor insertion into the disc space. Furthermore the angled strut lies ina plane at least substantially parallel to the plane of it's respectivewall, and in some embodiments to the long axis of the cage, so that theflexion does not alter the side wall thickness. This helps to maintainthe low profile for insertion while maximizing the lumen size. Thisgeometry combined with the solid beams on the corners helps ensure thatthe implant has a minimal change in length, less than 15% reduction inlength as measured along the long axis, when expanded more than 20%vertically and/or horizontally. As such, the top and bottom of the cagethat support the vertebra remain at least substantially constant inlength regardless of expansion.

In some embodiments, the cage 300 has v-shaped struts 333 and a bonegraft window 366 that (i) complements the v-shaped struts 333 in thecollapsed configuration and (ii) opens upon expansion to pass a bonegraft material into the intervertebral space in the open-complementaryconfiguration 355, which can also be referred to as an expandedconfiguration. And, in some embodiments, the cage 300 has a proximalregion 311, a proximal end 322, a distal region 388, a distal end 399,and at least one of the at least 4 walls 302,304,306,308 having a firstseries of v-shaped struts 333 that are configured to stack in aclosed-complementary configuration 344 in the collapsed state tominimize void space for the low profile entry of the cage 300 into theintervertebral space; and, deflect upon expansion to anopen-complementary configuration 355 to separate the at least 2longitudinal beams of the total of 4 longitudinal beams 312,314,316,318in the rectangular cylinder in their respective wall and open a bonegraft window 366 adapted to pass a bone graft material into theintervertebral space in the expanded configuration; wherein, the firstseries of v-shaped struts 333F is located in the proximal region of thecage, the vertices of the first series of v-shaped struts 333F pointingaway from the proximal end 322 of the cage 300 and toward the distal end399 of the cage 300. In some embodiments, the cage 300 can furthercomprise a second series of v-shaped struts 333S that stack in aclosed-complementary configuration 344 in the collapsed state tominimize void space for the low profile entry of the cage 300 into theintervertebral space; and, deflect upon expansion to anopen-complementary configuration 355 to separate the at least 2longitudinal beams of the total of 4 longitudinal beams 312,314,316,318in the rectangular cylinder in their respective wall and open a bonegraft window 366 adapted to pass a bone graft material into theintervertebral space in the expanded configuration; wherein, the secondseries of v-shaped struts 333S is located in the distal region 388 ofthe cage 300, the vertices of the second series of v-shaped struts 333Spointing away from the distal end 399 of the cage 300 and toward theproximal end 322 of the cage 300. In such embodiments, the strutconfiguration can result in the expansion of the first series ofv-shaped struts 333F and the second series of v-shaped struts 333Screating a bone graft window 366 that opens to the bow-tie configurationshown in FIGS. 3A and 3C.

One of skill will also appreciate that the cage design providesflexibility in the relative amounts of lateral expansion and verticalexpansion, as well as the relative amounts of expansion proximally anddistally across the cage in either the lateral or vertical expansions.As such, in some embodiments, the cage is configured such that the ratioof the amount of lateral expansion to the amount of vertical expansionis variable. And, in some embodiments, the cage is configured such thatthe ratio of the amount of proximal expansion to the amount of distalexpansion is variable for lateral expansion or vertical expansion.

FIGS. 4A and 4B illustrate collapsed and expanded views of abidirectionally-expandable cage having a bone graft window on each wallfor fusing an intervertebral disc space, according to some embodiments.FIG. 4A shows the cage 400 in the collapsed configuration for alow-profile entry 405 into to single point of entry into anintervertebral disc space, and FIG. 4B shows the cage 400 in theexpanded configuration to distract the intervertebral disc space andavoid back-out of the cage through the single point of entry after theexpansion. As shown, each wall contains a bone graft window 466 forpassing bone graft material into the intervertebral disc space.

FIGS. 5A-5D illustrate system for fusing an intervertebral disc space,according to some embodiments. As shown, the system 550 has a cage 555having an expandable/collapsible bone graft window 566; a shim core 560having a tapered nose 562 at the distal end of the shim core 560 and abone graft window 566; a releasably attachable rail beam 565; a pusher(not shown) that slidably translates over the shim core 560 and the railbeam 565; a trial shim 575 having a shoulder 577 and slidablytranslating over the rail beam 565 and shim core 560 into the cage 555,and a permanent shim 580 having a shoulder 582 and slidably translatingover the rail beam 565 and shim core 560 into the cage 555. The systemcan comprise a bidirectionally-expandable cage having at least 4 wallsthat form a cylinder having a long axis. The at least 4 walls caninclude, for example, a top wall forming a top plane and having a topsurface with protuberances adapted to contact the top vertebral plate; abottom wall forming a bottom plane and having a bottom surface withprotuberances adapted to contact the bottom vertebral plate; and, afirst side wall forming a first side wall plane, and a second side wallforming a second side wall plane. Each of the walls can have at least 2longitudinal beams; and, a plurality of struts that (i) stack in thecollapsed state to minimize void space in their respective wall for alow profile entry of the cage both vertically and laterally into asingle point of entry into an intervertebral disc; and, (ii) deflectupon expansion to separate the at least 2 longitudinal beams in theirrespective wall. In some embodiments, the cage can be configured toexpand laterally in the intervertebral space to a size greater than alateral dimension of the single point of entry to prevent thebidirectionally-expandable cage from backing out of the annulus fibrosisafter the expanding. Moreover, the system can include a lateroverticalexpansion member configured to induce the laterally expanding and thevertically expanding of the cage; and, a core configured to guide thelaterovertical expansion member into the cage to induce the laterallyexpanding and the vertically expanding of the cage.

One of skill will appreciate that the laterovertical expansion membercan also be configured to slidably engage with the core totranslationally enter the cage in along the long axis of the cage. Insome embodiments, the lateral expansion can occur concurrent with thevertical expansion and, in some embodiments, the lateral expansion canoccur prior to the vertical expansion, for example, to reduce frictionalstress on the cage during the lateral expansion. A two stage shim, forexample, can be used. A first stage shim can be inserted to expand thecage laterally before inserting a second stage shim to expand the cagevertically. In some embodiments, the second stage shim can slidablytranslate along the first stage shim. The shim can be made of anymaterial considered desirable to one of skill, for example, a metal or apolymer. In some embodiments, the shim can comprise a non-resorbablepolymer material, an inorganic material, a metal, an alloy, or bone.

One of skill will appreciate that a system can include all or anycombination of the above. As such, the teachings also include system forfusing an intervertebral disc space, the system comprising abidirectionally-expandable cage having a proximal region, a proximalend, a distal region, a distal end, and at least 4 walls, the cagefabricated as a continuous single piece. In these embodiments, the atleast 4 walls form a cylinder having a long axis and include a top wallforming a top plane and having a top surface with protuberances adaptedto contact the top vertebral plate; a bottom wall forming a bottom planeand having a bottom surface with protuberances adapted to contact thebottom vertebral plate; and, a first side wall forming a first side wallplane, and a second side wall forming a second side wall plane. Each ofthe walls can have at least 2 longitudinal beams and a plurality ofstruts.

At least one of the walls can have a first series of v-shaped strutsthat are configured to stack in a closed-complementary configuration inthe collapsed state to minimize void space for a low profile entry ofthe cage through a single point of entry into an intervertebral discspace; and, deflect upon expansion to an open-complementaryconfiguration to separate the at least 2 longitudinal beams in theirrespective wall and open a bone graft window adapted to pass a bonegraft material into the intervertebral space in the expandedconfiguration. The first series of v-shaped struts can be located in theproximal region of the cage, the vertices of the first series ofv-shaped struts pointing away from the proximal end of the cage andtoward the distal end of the cage; and, the cage can be configured toexpand laterally in the intervertebral space to a size greater than alateral dimension of the single point of entry to prevent thebidirectionally-expandable cage from backing out of the annulus fibrosisafter the expanding. A laterovertical expansion member can be configuredto induce the laterally expanding and the vertically expanding of thecage; and, a core can be configured to guide the lateroverticalexpansion member into the proximal end of the cage, and along the longaxis of the cage, to expand the cage laterally and vertically. Moreover,the laterovertical expansion member can slidably engage with the core totranslationally enter the cage along the long axis of the cage.

One of skill will appreciate that the systems and system components canbe manufactured using any method known to one of skill in themanufacture of such intricate metal and/or polymeric components. Forexample, the cage can be fabricated in a partially expanded state or afully expanded state. Moreover, the cage can be manufactured to have nointernal stress or strain in the partially or fully expanded state whenno external loading is applied.

The system components can comprise any suitable material, or anycombination of materials, known to one of skill. For example, allcomponents can be metal, all components can be plastic, or thecomponents can be a combination of metal and plastic. One of skill willappreciate that the cages can have performance characteristics that arenear that of a bone structure, in some embodiments, such that thescaffoldings are not too stiff or hard, resulting in a localized loadingissue in which the scaffolding puts too much pressure on native bonetissue, and likewise such that the scaffoldings are too flexible orsoft, resulting in a localized loading issue in which the bone tissueputs too much pressure on the scaffolding. A radio-opaque material canbe employed to facilitate identifying the location and position of thescaffolding in the spinal disc space. Examples of such materials caninclude, but are not limited to, platinum, tungsten, iridium, gold, orbismuth.

One of skill can select materials on the basis of desired materialperformance characteristics. For example, one of skill will look toperformance characteristics that can include static compression loading,dynamic compression loading, static torsion loading, dynamic torsionloading, static shear testing, dynamic shear testing, expulsion testing,and subsidence testing. The parameters for upper and lower limits ofperformance for these characteristics can fall within the range ofexisting such spinal devices that bear the same or similar environmentalconditions during use. For example, a desired static compression loadingcan be approximately 5000N. A desired dynamic compression loading canhave an asymptotic load level of ≧3000N at 5×10⁶ cycles or ≧1500N at10×10⁶ cycles. The desired load level can range, for example, from about1.0× to about 2.0×, from about 1.25× to about 1.75×, or any rangetherein in increments of 0.1×, the vertebral body compression strength.Examples of standard procedures used to test such performancecharacteristics include ASTM F2077 and ASTM F2624.

Examples of suitable materials can include non-reinforced polymers,carbon-reinforced polymer composites, PEEK (polyether ketone) and PEEKcomposites, polyetherimide (ULTEM), polyimide, polyamide or carbonfiber. Other examples include metals and alloys comprising any one ormore components including, but not limited to, shape-memory alloys,nickel, titanium, titanium alloys, cobalt chrome alloys, stainlesssteel, ceramics and combinations thereof. In some embodiments, thecomponents are all titanium or titanium alloy; all PEEK; or acombination of titanium or titanium alloy and PEEK. In some embodiments,the cage comprises titanium or titanium alloy, and the shim comprisesPEEK. In some embodiments, the scaffolding can comprise a metal frameand cover made of PEEK or ULTEM. Examples of titanium alloys can includealloys of titanium, aluminum, and vanadium, such as Ti₆Al₄V in someembodiments.

In some embodiments, the cage can be fabricated from strong and ductilepolymers having a tensile modulus of about 400,000 psi or more, and atensile strength of about 14,000 psi or more. Such polymers may alsohave the ability to strain more than 4% to break, and perhaps at least20% to break in some embodiments. The materials can be stiffened bybeing filled with glass fibers or carbon fibers in some embodiments.

Bone ingrowth is desirable in many embodiments. As such, the scaffoldingcan comprise materials that contain holes or slots to allow for suchbone ingrowth. Consistently, the scaffoldings can be coated withhydroxyapatite, or other bone conducting surface, for example, bonemorphogenic protein, to facilitate bone ingrowth. Moreover, the surfacesof the scaffoldings can be formed as rough surfaces with protuberances,insets, or projections of any type known to one of skill, such as teethor pyramids, for example, to grip vertebral endplates, avoid migrationof the scaffolding, and encourage engagement with bone ingrowth.

The methods and systems provided herein include the use of bone graftmaterials known to one of skill. Materials which may be placed orinjected into the intevertebral space include solid or semi-solidgrafting materials, bone from removed from patient's facet, an iliaccrest harvest from the patient, and bone graft extenders such ashydroxyapatite, demineralized bone matrix, and bone morphogenic protein.Examples of solid or semi-solid grafting material components includesolid fibrous collagen or other suitable hard hydrophilic biocompatiblematerial. Some materials may also include swelling for further verticalexpansion of the intervertebral disc space.

The systems taught herein can be provided to the art in the form ofkits. A kit can contain, for example, a cage, a vertical expansionmember, and a bone graft material. In some embodiments, the kit willcontain an instruction for use. The vertical expansion member can be anyvertical expansion mechanism or means taught herein. For example, thevertical expansion member can be a shim. In some embodiments, the kitincludes a graft-injection shim for temporarily distracting theintervertebral space, the graft-injection shim having a port forreceiving and distributing the bone graft material in the intervertebralspace. In these embodiments, the graft-injection shim can remain as apermanent shim or be removed and replaced with a permanent shim.

FIG. 6 is a flowchart of a method of using a bidirectionally-expandablecage, according to some embodiments. The methods can include creating605 a single point of entry into an intervertebral disc, theintervertebral disc having a nucleus pulposus surrounded by an annulusfibrosis, and the single point of entry having a lateral dimensioncreated through the annulus fibrosis. The methods can also includeremoving 615 the nucleus pulposus from within the intervertebral throughthe single point of entry, leaving an intervertebral space for expansionof a bidirectionally-expandable cage within the annulus fibrosis, theintervertebral space having a top vertebral plate and a bottom vertebralplate. The methods can also include inserting 625 abidirectionally-expandable cage through the single point of entry intothe intervertebral space. Moreover, the methods can include expanding635 the cage in the intervertebral space both laterally and vertically,adding 645 a grafting material to the intervertebral space through thesingle point of entry, and inserting 665 a permanent shim into the cage.

One of skill will appreciate having the ability to control the amountsof vertical expansion and lateral expansion of the cage to accommodate avariety of applications, for example, to accommodate a varietyannulotomy dimensions used for the single point of entry. As such, insome embodiments, the expanding 635 includes selecting 655 an amount oflateral expansion independent of an amount of vertical expansion. Thelateral expanding of the cage can be selected, for example, to exceedthe lateral dimension of the single point of entry through an annulotomyby a desired amount to avoid, or prevent, the cage from backing out ofthe intervertebral space after expansion.

As such, methods of fusing an intervertebral space are provided hereinusing any of the graft distribution systems taught herein. The methodscan include creating a single point of entry into an intervertebraldisc, the intervertebral disc having a nucleus pulposus surrounded by anannulus fibrosis, and the single point of entry having the maximumlateral dimension created through the annulus fibrosis. The methods canalso include removing the nucleus pulposus from within theintervertebral disc through the single point of entry, leaving theintervertebral space for expansion of the graft distribution systemwithin the annulus fibrosis, the intervertebral space having the topvertebral plate and the bottom vertebral plate. The methods can alsoinclude inserting the laterovertically expanding frame in the collapsedstate through the single point of entry into the intervertebral space;and, inserting the central beam into the frame to form the graftdistribution system. Moreover, the methods can also include adding agrafting material to the intervertebral space through the entry port.

FIGS. 7A-7F illustrate some additional features of graft distributionsystems, according to some embodiments. The graft distribution systems700 provided herein have at least a top exit port 740 and a bottom exitport 741 in the grafting portion of the central beam 701, but they canalso contain side ports 742,743, such that there at least 4 graftdistribution ports in some embodiments. In some embodiments, the centralbeam 701 further comprises a first side graft port 742 and a second sidegraft port 743, in addition to a locking clip 702 at the proximal end ofthe central beam. In some embodiments, the laterovertically-expandingframe 749 can be a monolithically integral frame, optionally having a“bullet nose” 703 at the distal end of the frame for safe position ofthe cage against the anterior inner annulus in vivo, and adapted to opena graft distribution window 788 on at least the top and bottom sides, aswell as the first side and second side in some embodiments containingside ports, upon expansion of the connector elements to facilitate graftdistribution within the intervertebral space.

The distal end of the frame 749 can be configured to have alaterovertically operable connection with a guide plate 707 thatrestricts the first top beam, the first bottom beam, the second topbeam, and the second bottom beam to laterovertical movement relative tothe guide plate when converting the frame from the collapsed state tothe expanded state in vivo. And, in some embodiments, thelaterovertically-expandable frame has a lumen, and the guide plate has aluminal side with a connector 708 for reversibly receiving a guide wirefor inserting the laterovertically-expandable frame into theintervertebral space. In some embodiments, the frame has a chamferinside the proximal end of the frame beams to facilitate insertion ofcentral beam. And, in many embodiments, the frames have means forcreating friction between the vertebral endplates and the frame, such asprotuberances, for example cleat-type structures 704, to further avoidbackout.

As can be seen in at least FIG. 7, the bone graft distribution systemsprovided herein include bone graft windows defined by the connectorelements, the bone graft windows opening upon expansion of thelaterovertically expanding frame. In some embodiments, the methodfurther comprises opening a bone graft window, wherein the connectorelements include v-shaped struts that (i) stack either proximally ordistally in a closed-complementary configuration in the collapsed stateto minimize void space for a low profile entry of the system bothvertically and laterally into the intervertebral space, and (ii) deflectupon expansion to open the bone graft window.

It should be appreciated that the bone graft distribution systemsprovided herein also allow for independent expansion laterally andvertically by expanding in steps. In some embodiments, the expandingincludes selecting an amount of lateral expansion independent of anamount of vertical expansion. And, in some embodiments, the lateralexpansion exceeds the width of the annular opening that is the singlepoint of entry into the intervertebral space. For example, the lateraldimension of the single point of entry can range from about 5 mm toabout 15 mm in some embodiments. As such, in some embodiments, theexpanding includes expanding the laterovertically expanding framelaterally to a width that exceeds the width of the single point ofentry; and, inserting the central beam to expand the lateroverticallyexpanding frame vertically to create the graft distribution system.

The bone graft distribution systems provided herein also have additionalmeans for retaining the central beam in the laterovertically expandingframe. In some embodiments, the inserting of the central beam into thelaterovertically expanding frame includes engaging a ratchet mechanismcomprising a protuberance on the central beam that engages with thelaterovertically-expanding frame to prevent the central beam frombacking out of the laterovertically-expanding frame after the expanding.

Moreover, the bone graft distribution systems provided herein can be inthe form of a kit. The kits can include, for example, a graftdistribution system taught herein, a cannula for inserting the graftdistribution system into the intervertebral space, a guidewire adaptedfor guiding the central beam into the laterovertically expanding frame,and an expansion handle for inserting the central beam into thelaterovertically expanding frame to form the graft distribution system.

FIGS. 8A-8D illustrate components of a kit, according to someembodiments. FIGS. 8A and 8B illustrate a 4-sided funnel cannula 805 astaught herein having a shaft 810 forming a channel 815, a funnel 820 forguiding a laterovertically expandable frame into an annulus in alow-profile configuration, the cannula shown with an obturator 825 inthe channel 815 of the cannula 805, the cannula 805 insertedposterolaterally through an annulotomy 877 in the annulus 888, into anintervertebral space 899, with the distal end of the cannula 805position near the inner anterior wall of the annulus 888. FIG. 8Cillustrates FIG. 8A with a guidewire used to insert the lateroverticallyexpandable frame 749 into the funnel 820 of the cannula 805 to guide theframe 749 into the annulus 888 in the low profile, collapsed state ofthe frame 749. FIG. 8D illustrates an expansion handle 855 havingtrigger 856 that pushes a pushrod 857 along the guidewire 866 whileholding the guidewire to push on the proximal end of the central beam701 to insert the central beam 701 into the frame 749 to expand theframe 749 by applying equal, or substantially equal forces: aproximally-directed force, F_(P), at the connection 708 between theguide plate 707 and the guide wire 866 onto the distal portion of thebeams of the frame 749, and a distally-directed force, F_(D), at theproximal end of the central beam 701.

FIGS. 9A-9C illustrate the expansion of a laterovertically-expandableframe in an intervertebral space, according to some embodiments. FIG. 9Ashows a collapsed frame 949 receiving a central beam 901 along aguidewire 966. FIG. 9B shows the central beam 901 partially insertedinto the frame 949 in an expanded state, the guidewire 966 still inplace FIG. 9C shows how the expanded state may appear when insertedposterolaterally and expanded in the intervertebral space in an annulus988. Side ports 942,943 for bone graft distribution are shown through anopen bone graft window in the expanded frame 749.

FIGS. 10A-10C illustrate profiles of an expanded graft distributionsystem to highlight the exit ports and bone graft windows, according tosome embodiments. Profiles of an expanded frame 1049, highlighting bonegraft windows 1088 and graft ports 1040,1041,1042,1043 as they mayappear in an intervertebral space after an implant procedure. Theguidewire 1066 is shown as remaining in place.

FIGS. 11A and 11B compare an illustration of the graft distribution inplace to a test placement in a cadaver to show relative size, accordingto some embodiments. Likewise, FIGS. 12A-12C show x-rays of a placementin a cadaver, according to some embodiments.

As described above, the frame 149 can be configured such that thecentral axis of the first top beam 150 is at least substantially on (i)the top plane and (ii) the first side plane; the central axis of thesecond top beam 160 is at least substantially on (i) the top plane and(ii) the second side plane; the central axis of the first bottom beam170 is at least substantially on (i) the bottom plane and (ii) the firstside plane; and, the central axis of the second bottom beam being atleast substantially on (i) the bottom plane and (ii) the second sideplane. It should be appreciated that this configuration provides a “topface” framed by the first top beam and the second top beam, a “bottomface” framed by the first bottom beam and the second bottom beam, a“first side face” framed by the first top beam and the first bottombeam, and a “second side face” framed by the second top beam and thesecond bottom beam.

In some embodiments, it can be desirable to have the frame expand toshape that is predesigned to fit between the top endplate and the bottomendplate of the intervertebral space in a manner that calls, forexample, for opposing faces of the frames to be something other than “atleast substantially parallel.” For example, it may be desired to havethe two opposing sides of the frame expand such that the central axis ofthe first top beam is no longer at least substantially parallel to thecentral axis of the second top beam. Likewise, it may be desired to havethe two opposing sides of the frame expand such that the central axis ofthe first bottom beam is no longer at least substantially parallel tothe central axis of the second bottom beam. Likewise, it may be desiredto have the opposing top and bottom sides of the frame expand such thatthe central axis of the first top beam is no longer at leastsubstantially parallel to the central axis of the first bottom beam.Likewise, it may be desired to have the opposing top and bottom sides ofthe frame expand such that the central axis of the second top beam is nolonger at least substantially parallel to the central axis of the secondbottom beam. Or, any combination of the above may be desired. Thelaterovertically expandable frames taught herein enable each of thesedesirable configurations.

FIGS. 13A-13D show orientations of the first top beam relative to thesecond top beam, first bottom beam relative to the second bottom beam,first top beam relative to the first bottom beam, and the second topbeam relative to the second bottom beam, according to some embodiments.FIG. 13A shows the first top beam 150 relative to the second top beam160, in which the angle θ_(T) is formed by the two beams to shape thetop face of the frame. FIG. 13B shows the first bottom beam 170 relativeto the second bottom beam 180, in which the angle θ_(B) is formed by thetwo beams to shape the bottom face of the frame. FIG. 13C shows thefirst top beam 150 relative to the first bottom beam 170, in which theangle θ_(FS) is formed by the two beams to shape the first side face ofthe frame. FIG. 13D shows the second top beam 160 relative to the secondbottom beam 180, in which the angle θ_(SS) is formed by the two beams toshape the second side face of the frame. In some embodiments, each ofθ_(T), θ_(B), θ_(FS), and θ_(SS) can be independently selected and eachcan range from 0° to 32°, from 0.5° to 31.5°, from 0.1° to 31.0°, from1.5° to 30.5°, from 2.0° to 30.0°, from 2.5° to 29.5°, from 3.0° to29.0°, from 3.5° to 28.5°, from 4.0° to 28.0°, from 4.5° to 27.5°, from5.0° to 27°, from 5.5° to 26.5°, from 6.0° to 26.0°, from 6.5° to 25.5°,from 7.0° to 25.0°, from 7.5° to 25.5°, from 8.0° to 26.0°, from 8.5° to26.5°, from 9.0° to 26.0°, from 9.5° to 25.5°, from 10.0° to 25.0°, from10.5° to 24.5°, from 11.0° to 24.0°, from 11.5° to 23.5°, from 12.0° to23.0°, from 12.5° to 22.5°, from 13.0° to 22.0°, from 13.5° to 21.5°,from 14.5° to 21.0°, from 15.5° to 20.5°, from 16.0° to 20.0°, from16.5° to 19.5°, from 17.0° to 19.0°, or any range therein in incrementsof 0.1°. In some embodiments, each of θ_(T), θ_(B), θ_(FS), and θ_(SS)can be independently selected and each can be about 1°, 2°, 3°, 4°, 5°,6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°,21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°,35°, or any angle therein in increments of 0.1°.

It should be appreciated that the beams can each be independentlydesigned to have its own, independently selected curvature, whetherconvex or concave, and the curvatures can be the same or differentbetween beams that share a face of the frame. And, the curvatures can beopposing for beams that form opposing faces of the frame. Moreover, theframe can have a mixture of one or more straight and one or more curvedbeams.

Given the above, it should be appreciated that the frames can bedesigned according to nearly any opening bordered by the top vertebralendplate and bottom vertebral endplate of an intervertebral space, aswell as according to a given clinical treatment regardless of theopening dimensions prior to treatment. In some embodiments, the top faceof the frame can be at least substantially parallel to the bottom faceof the frame, whereas the first side face of the frame and the secondside face of the frame can be oriented at angles θ_(T) and θ_(B),wherein θ_(T) and θ_(B) can be independently selected to be the same ordifferent. Likewise, in some embodiments, the first side face of theframe can be at least substantially parallel to the second side face ofthe frame, whereas the top face of the frame and the bottom face of theframe can be oriented at angles θ_(FS) and θ_(SS), wherein θ_(FS)andθ_(SS) can be independently selected to be the same or different. Insome embodiments, each of θ_(T), θ_(B), θ_(FS), and θ_(SS) can beindependently selected to range from about 5° to about 32°, from about7° to about 22°, and from about 8° to about 16°, in some embodiments. Assuch, any of a variety of frames can be constructed from any of avariety of quadrilateral structures having the angles taught herein.

In some embodiments, the systems include a stabilizer that slidablyengages with the distal region of the first top beam, the first bottombeam, the second top beam, the second bottom beam, or a combinationthereof. The stabilizer serves the function of the guide plate taughtherein and can also be configured for retaining the first top beam, thefirst bottom beam, the second top beam, the second bottom beam, or thecombination thereof, from a lateral movement that exceeds the expandedstate.

And, in some embodiments, the framing can be configured for engagingwith the central beam in vivo to support the framing in the expandedstate. Moreover, the connector elements can be struts configured to havea cross-sectional aspect ratio of longitudinal thickness to transversethickness ranging from 1:2 to 1:8, adapted to maintain structuralstiffness in the laterovertically expanding frame in a directionperpendicular to the central frame axis of the expanded state of theframe.

FIGS. 14A-14D illustrate components of a system having a stabilizer,wherein the stabilizer is in an X-configuration, according to someembodiments. As shown in FIG. 14A, the system 1400 can include astabilizer 1407 that can be in an X-configuration. In some embodiments,the X-configuration can have a first top leg TL, for slidably-engagingwith the first top beam 1450 at an angle θ_(1T) with the intendedlateral movement LM_(1T) of the first top beam 1450, first bottom legBL₁ for slidably engaging with the first bottom beam 1470 at an angleθ_(1B) with the intended lateral movement LM_(1B) of the first bottombeam 1470, a second top leg TL₂ for slidably engaging with the secondtop beam 1480 at an angle θ_(2T) with the intended lateral movementLM_(2T) of the second top beam 1460, and a second bottom leg BL₂ forslidably engaging with the second bottom beam 1480 at an angle θ_(2B)with the intended lateral movement LM_(2B) of the second bottom beam1480.

In some embodiments, each of the angles θ_(1T), θ_(1B), θ_(2T), θ_(2B),respectively, provide a tensile force for resisting the first top beam1450, the first bottom beam 1470, the second top beam 1460, and thesecond bottom beam 1480 from the lateral movement LM_(1T),LM_(2T),LM_(1B),LM_(2B) that exceeds the expanded state. In someembodiments, each of the angles θ_(1T), θ_(1B), θ_(2T), θ_(2B) can beindependently selected from an amount of angulation ranging from about15° to about 75°, from about 20° to about 75°, from about 25° to about75°, from about 30° to about 75°, from about 35° to about 75°, fromabout 55° to about 75°, from about 15° to about 70°, from about 15° toabout 65°, from about 15° to about 60°, from about 15° to about 55°,from about 15° to about 50°, from about 15° to about 45°, or any rangetherein. In some embodiments, each of the angles θ_(1T), θ_(1B), θ_(2T),θ_(2B) can be independently selected from an amount of angulation thatis about 10°, about 15°, about 20°, about 25°, about 30°, about 35°,about 40°, about 45°, about 50°, about 55°, about 60°, about 65°, about70°, about 75°, about 80°, or any angulation therein in amounts of 1°.

In some embodiments, the stabilizer 1407 further comprises a point ofattachment 1408 for releasably attaching a guidewire (not shown) forguiding the central beam 1401 into the laterovertically expanding framecomprising the first top beam 1450, the second top beam 1460, the firstbottom beam 1470, and the second bottom beam 1480. And, in someembodiments, the first top leg TL₁, the first bottom leg BL₁, the secondtop leg TL₂, and the second bottom leg BL₂ converge to form a hub 1408Hhaving a point of attachment 1408 on the posterior surface of the hub1408H for releasably attaching a guidewire (not shown) for guiding thecentral beam 1401 into the laterovertically expanding frame. The pointof attachment might be, for example, a male or female threadedcomponent, or any other releasable connector known to one of skill. And,the beams 1450,1460,1470,1480 can be configured with ports TP₁,TP₂,BP₁,BP₂ for passage of the respective legs TL₁,TL₂,BL₁,BL₂ of thestabilizer 1407. FIGS. 14B and 14C show the system in a collapsedconfiguration and expanded side configuration, respectively. In someembodiments, the central beam 1401 can include one or more bone graftdistribution ports 1466. And, as in other embodiments taught herein, thebeams 1450,1460,1470,1480 can be interconnected using flexible struts1495.

FIGS. 15A-15D illustrate components of a system having a stabilizer,wherein the stabilizer is in an H-configuration, according to someembodiments. The H-configuration can have a first vertical leg VL₁, asecond vertical leg VL₂, and a cross-member CM that connects the firstvertical leg VL₁ at least substantially parallel to the second verticalleg VL₂, the first vertical leg VL₁ including a first retaining surfaceRS₁ for engaging with the first top beam 1550 and the first bottom beam1570, the second vertical leg VL₂ including a second retaining surfaceRS₂ for engaging with the second top beam 1560 and the second bottombeam 1580, and the cross member CM providing a tensile force forresisting the first top beam 1550, the first bottom beam 1570, thesecond top beam 1560, and the second bottom beam 1580 from the lateralmovement that exceeds the expanded state. In some embodiments, thecentral beam 1501 has a horizontal groove HG configured complementary tothe cross-member CM of the stabilizer 1507, and the horizontal groove HGof the central beam 1501 slidably connects with the cross-member CM inthe expanded state. In some embodiments, the cross-member CM furthercomprises a vertical support member VSM and the central beam 1501 has avertical groove VG configured complementary to the vertical supportmember VSM of the stabilizer, and the vertical groove VG of the centralbeam 1501 slidably connects with the vertical support member VSM in theexpanded state. In some embodiments, the stabilizer 1507 furthercomprises a point of attachment 1508 at a hub 1508H for releasablyattaching a guidewire (not shown) adapted for guiding the central beam1501 into the laterovertically expanding frame comprising the first topbeam 1550, the second top beam 1560, the first bottom beam 1570, and thesecond bottom beam 1580. guidewire (not shown) for guiding the centralbeam 1501 into the laterovertically expanding frame. The point ofattachment might be, for example, a male or female threaded component,or any other releasable connector known to one of skill. And, the beams1550,1560,1570,1580 can be configured with slots S₁,S₂ in which thevertical legs VL₁,VL₂ can travel during the lateral expansion of thebeams 1550,1560,1570,1580 of the expandable frame. And, in someembodiments, cross-member CM includes a first pillar P₁ and a secondpillar P₂ that operably connect at a hub that has the point ofattachment 1508 for releasably attaching the guidewire (not shown) forguiding the central beam 1501 into the laterovertically expanding frame.In some embodiments, the central beam 1501 can include one or more bonegraft distribution ports 1566. And, as in other embodiments taughtherein, the beams 1550,1560,1570,1580 can be interconnected usingflexible struts 1595.

One of skill will appreciate that the teachings provided herein aredirected to basic concepts that can extend beyond any particularembodiment, embodiments, figure, or figures. It should be appreciatedthat any examples are for purposes of illustration and are not to beconstrued as otherwise limiting to the teachings. For example, it shouldbe appreciated that the devices provided herein can also be used asimplants in other areas of the body. The devices provided herein can beused, for example, in intravertebral body procedures to support ordistract vertebral bodies in the repair of, for example, collapsed,damaged or unstable vertebral bodies suffering from disease or injury.

We claim:
 1. An intervertebral scaffolding system, comprising; alaterovertically-expanding frame configured to create an intervertebralscaffolding system in vivo, the frame having a collapsed state and anexpanded state, the expanded state operably contacting theintervertebral space; a proximal portion having an end, a distal portionhaving an end, and a central frame axis of the expanded state; a firsttop beam including a proximal portion having an end and a distal portionhaving an end, the central axis of the first top beam at leastsubstantially on (i) a top plane containing the central axis of thefirst top beam and a central axis of a second top beam and (ii) a firstside plane containing the central axis of the first top beam and acentral axis of a first bottom beam; the second top beam including aproximal portion having an end and a distal portion having an end, thecentral axis of the second top beam at least substantially on (i) thetop plane and (ii) a second side plane containing the central axis ofthe second top beam and a central axis of a second bottom beam; thefirst bottom beam including a proximal portion having an end and adistal portion having an end, the central axis of the first bottom beamat least substantially on (i) a bottom plane containing the central axisof the first bottom beam and the central axis of the second top beam and(ii) the first side plane; the second bottom beam including a proximalportion having an end and a distal region having an end, the centralaxis of the second bottom beam being at least substantially on (i) thebottom plane and (ii) a second side plane containing the central axis ofthe second bottom beam and the central axis of the second top beam; aplurality of top connector elements configured to expandably connect thefirst top beam to the second top beam, the expanding consisting of aflexing at least substantially on the top plane; a plurality of bottomconnector elements configured to expandably connect the first bottombeam to the second bottom beam, the expanding consisting of a flexing atleast substantially on the bottom plane; a plurality of first sideconnector elements configured to expandably connect the first top beamto the first bottom beam, the expanding consisting of a flexing at leastsubstantially on the first side plane; a plurality of second sideconnector elements configured to expandably connect the second top beamto the second bottom beam, the expanding consisting of a flexing atleast substantially on the second side plane; and, a stabilizer thatslidably engages with the distal region of the first top beam, the firstbottom beam, the second top beam, the second bottom beam, or acombination thereof, and is configured for retaining the first top beam,the first bottom beam, the second top beam, the second bottom beam, orthe combination thereof, from a lateral movement that exceeds theexpanded state; wherein, the connector elements are configured tomaintain structural stiffness in the laterovertically-expanding frame.2. The scaffolding system of claim 1, wherein the stabilizer is in anX-configuration having a first top leg for slidably-engaging with thefirst top beam at an angle θ_(1T) with the lateral movement of the firsttop beam, first bottom leg for slidably engaging with the first bottombeam at an angle θ_(1B) with the lateral movement of the first bottombeam, a second top leg for slidably engaging with the second top beam atan angle θ_(2T) with the lateral movement of the second top beam, and asecond bottom leg for slidably engaging with the second bottom beam atan angle θ_(2B) with the lateral movement of the second bottom beam,wherein each of the angles θ_(1T), θ_(1B), θ_(2T), θ_(2B), respectively,provide a tensile force for resisting the first top beam, the firstbottom beam, the second top beam, and the second bottom beam from thelateral movement that exceeds the expanded state.
 3. The scaffoldingsystem of claim 1, wherein the stabilizer is in an X-configurationhaving a first top leg for slidably-engaging with the first top beam atan angle θ_(1T) with the lateral movement of the first top beam, firstbottom leg for slidably engaging with the first bottom beam at an angleθ_(1B) with the lateral movement of the first bottom beam, a second topleg for slidably engaging with the second top beam at an angle θ_(2T)with the lateral movement of the second top beam, and a second bottomleg for slidably engaging with the second bottom beam at an angle θ_(2B)with the lateral movement of the second bottom beam, wherein each of theangles θ_(1T), θ_(1B), θ_(2T), θ_(2B), respectively, provide a tensileforce for resisting the first top beam, the first bottom beam, thesecond top beam, and the second bottom beam from the lateral movementthat exceeds the expanded state; wherein, the system further comprisesan expansion member, and the stabilizer further comprises a point ofattachment for releasably attaching a guidewire for guiding theexpansion member into the laterovertically expanding frame.
 4. Thescaffolding system of claim 1, wherein the stabilizer is in anX-configuration having a first top leg for slidably-engaging with thefirst top beam at an angle θ_(1T) with the lateral movement of the firsttop beam, first bottom leg for slidably engaging with the first bottombeam at an angle θ_(1B) with the lateral movement of the first bottombeam, a second top leg for slidably engaging with the second top beam atan angle θ_(2T) with the lateral movement of the second top beam, and asecond bottom leg for slidably engaging with the second bottom beam atan angle θ_(2B) with the lateral movement of the second bottom beam,wherein each of the angles θ_(1T), θ_(1B), θ_(2T), θ_(2B), respectively,provide a tensile force for resisting the first top beam, the firstbottom beam, the second top beam, and the second bottom beam from thelateral movement that exceeds the expanded state; wherein, the systemfurther comprises an expansion member, and the first top leg, the firstbottom leg, the second top leg, and the second bottom leg converge toform a hub having a point of attachment for releasably attaching aguidewire for guiding the expansion member into the lateroverticallyexpanding frame.
 5. The scaffolding system of claim 1, wherein thestabilizer is in an H-configuration having a first vertical leg, asecond vertical leg, and a cross-member that connects the first verticalleg at least substantially parallel to the second vertical leg, thefirst vertical leg including a retaining surface for engaging with thefirst top beam and the first bottom beam, the second vertical legincluding a retaining surface for engaging with the second top beam andthe second bottom beam, and the cross member providing a tensile forcefor resisting the first top beam, the first bottom beam, the second topbeam, and the second bottom beam from the lateral movement that exceedsthe expanded state.
 6. The scaffolding system of claim 1, wherein thestabilizer is in an H-configuration having a first vertical leg, asecond vertical leg, and a cross-member that connects the first verticalleg at least substantially parallel to the second vertical leg, thefirst vertical leg including a retaining surface for engaging with thefirst top beam and the first bottom beam, the second vertical legincluding a retaining surface for engaging with the second top beam andthe second bottom beam, and the cross member providing a tensile forcefor resisting the first top beam, the first bottom beam, the second topbeam, and the second bottom beam from the lateral movement that exceedsthe expanded state; wherein, the system further comprises an expansionmember with a horizontal groove configured complementary to thecross-member of the stabilizer, and the horizontal groove of theexpansion member slidably connects with the cross-member in the expandedstate.
 7. The scaffolding system of claim 1, wherein the stabilizer isin an H-configuration having a first vertical leg, a second verticalleg, a cross-member that connects the first vertical leg at leastsubstantially parallel to the second vertical leg, the first verticalleg including a retaining surface for engaging with the first top beamand the first bottom beam, the second vertical leg including a retainingsurface for engaging with the second top beam and the second bottombeam, and the cross member providing a tensile force for resisting thefirst top beam, the first bottom beam, the second top beam, and thesecond bottom beam from the lateral movement that exceeds the expandedstate; wherein, the system further comprises an expansion member, andthe cross-member further comprises a vertical support member, theexpansion member having a vertical groove configured complementary tothe vertical support member of the stabilizer, and the vertical grooveof the expansion member slidably connects with the vertical supportmember in the expanded state.
 8. The scaffolding system of claim 1,wherein the stabilizer is in an H-configuration having a first verticalleg, a second vertical leg, a cross-member that connects the firstvertical leg at least substantially parallel to the second vertical leg,the first vertical leg including a retaining surface for engaging withthe first top beam and the first bottom beam, the second vertical legincluding a retaining surface for engaging with the second top beam andthe second bottom beam, and the cross member providing a tensile forcefor resisting the first top beam, the first bottom beam, the second topbeam, and the second bottom beam from the lateral movement that exceedsthe expanded state; wherein, the system further comprises an expansionmember, and the stabilizer further comprises a point of attachment forreleasably attaching a guidewire adapted for guiding the expansionmember into the laterovertically expanding frame.
 9. The scaffoldingsystem of claim 1, wherein the stabilizer is in an H-configurationhaving a first vertical leg, a second vertical leg, a cross-member thatconnects the first vertical leg at least substantially parallel to thesecond vertical leg, the first vertical leg including a retainingsurface for engaging with the first top beam and the first bottom beam,the second vertical leg including a retaining surface for engaging withthe second top beam and the second bottom beam, and the cross memberproviding a tensile force for resisting the first top beam, the firstbottom beam, the second top beam, and the second bottom beam from thelateral movement that exceeds the expanded state; wherein, the systemfurther comprises an expansion member, and the cross-member includes afirst pillar and a second pillar that operably connect at a hub that hasa point of attachment for releasably attaching a guidewire for guidingthe expansion member into the laterovertically expanding frame.
 10. Thescaffolding system of claim 1 further comprising a grafting port. 11.The scaffolding system of claim 1, wherein each plurality connectorelements are struts; and. wherein, the top struts are configuredmonolithically integral to the first top beam and the second top beam;and, the bottom struts are configured monolithically integral to thefirst bottom beam and the second bottom beam; wherein, the top strutsand bottom struts of the laterovertically-expanding frame are eachconfigured to open a graft distribution window upon expansion, expandingfrom the first top beam to the second top beam, the first top beam tothe first bottom beam, the second top beam to the second bottom beam, orthe first bottom beam to the second bottom beam.
 12. The scaffoldingsystem of claim 1, wherein, the top connector struts are configuredmonolithically integral to the first top beam and the second top beam;and, the bottom struts are configured monolithically integral to thefirst bottom beam and the second bottom beam; the first side struts areconfigured monolithically integral to the first top beam and the firstbottom beam; and, the second side struts are configured monolithicallyintegral to the second top beam and the second bottom beam; wherein, thetop, bottom, first side, and second side of thelaterovertically-expanding frame form a monolithically integral frame.13. A method of fusing an intervertebral space using the scaffoldingsystem of claim 1, the method comprising: creating a point of entry intoan intervertebral disc, the intervertebral disc having a nucleuspulposus surrounded by an annulus fibrosis; removing the nucleuspulposus from within the intervertebral disc through the point of entry,leaving the intervertebral space for expansion of the scaffolding systemof claim 1 within the annulus fibrosis, the intervertebral space havinga top vertebral plate and a bottom vertebral plate; inserting thelaterovertically expanding frame in the collapsed state through thepoint of entry into the intervertebral space; expanding thelaterovertically expanding frame to form the scaffolding system; and,adding a grafting material to the intervertebral space.
 14. The methodof claim 13, wherein the creating the point of entry comprises creatinga lateral dimension of the point of entry ranging from about 5 mm toabout 15 mm, and the amount of lateral expansion is selected to exceedthe lateral dimension of the point of entry.
 15. The method of claim 13,wherein the expanding includes expanding the laterovertically expandingframe laterally to a width that exceeds the width of the point of entry;and, expanding the laterovertically expanding frame vertically tosupport the intervertebral space in the expanded state.
 16. The methodof claim 13, wherein the expanding the laterovertically expanding frameincludes inserting an expansion member and engaging a means forpreventing the expansion member from backing out of thelaterovertically-expanding frame after the expanding.
 17. A kit,comprising: the scaffolding system of claim 1; a cannula for insertingthe scaffolding system into the intervertebral space; and, a guidewireadapted for guiding an expansion member into the lateroverticallyexpanding frame.
 18. A kit, comprising: the scaffolding system of claim2; a cannula for inserting the scaffolding system into theintervertebral space; and, a guidewire adapted for guiding an expansionmember into the laterovertically expanding frame.
 19. A kit, comprising:the scaffolding system of claim 4; a cannula for inserting thescaffolding system into the intervertebral space; and, a guidewireadapted for guiding the expansion member into the lateroverticallyexpanding frame.
 20. A kit, comprising: the scaffolding system of claim6; a cannula for inserting the scaffolding system into theintervertebral space; and, a guidewire adapted for guiding the expansionmember into the laterovertically expanding frame.